sir as you said that testis develop in abdominal region and decend down,but in some it doesn't descend down then the male can become infertile?
Yes the male becomes infertile
It was become the spermiogenesis will not occur. It will only occur at temp lower than body temp. That temp will only provided by scrotum. If spermiogenesis will not occur male become infertile.
THIS CONDITION IS KNOWN AS CRYPTORCHIDISM WHICH CAN BE CURED BY OPERATION IF THE OPERATION FAILS THAN MALE BECOME INFERTILE